OBJECTIVES: 1. Methodology for the separation and identification of bacterial metabolites of 17 alpha-hydroxycorticoids. 2. Prevalence in fecal flora of human and rat of organisms synthesizing dehydroxylase, desmolase, and oxido-reductases with particular emphasis on 16, 17, and 21 position of the steroid concentration, temperature, pH, redox potential and kinetics. 4. Stimulating and suppressing factors. 5. Identification of bacterial species synthesizing the specific enzymes. 6. Search for similar enzymatic systems in genetically closely related organisms. 7. Determination of bacterially mediated metabolic pathways of steroids undergoing enterohepatic circulation. 8. Biosysnthesis of steroid standards not commercially available.